Willie Nelson didn't expect to live beyond the age of 21.

The 93-year-old singer admitted he drank too much and took too many drugs in his younger years, to the extent that everyone around him expected his life to end prematurely, but he gave up alcohol and all illegal substances except marijuana in 1978 and believes sobriety saved his life.

Asked if he ever imagined he'd still be performing and recording in his 90s, he told the Guardian newspaper: "No. The way I was going, I never expected to be here.

"I don't think anyone expected me to live beyond 21, the way I was going.

"I did everything wrong. If it was wrong, I did it. And if it was really wrong, I did it twice.

"I drank too much, I smoked too much. I took too many pills. [What pills?] Oh, I don't know. Little white ones."

The On the Road Again hitmaker feels "lucky" to still be alive but views dying as a natural part of life.

He said: "I guess I probably am the last leaf on the tree. I'm lucky to be here. I've lost a lot of my good friends along the way. You know, Johnny [Cash], Waylon [Jennings] and Kris [Kristofferson]. I feel fortunate that I'm still here.

"Well, you know, everybody's gonna die, so it ain't no big deal how long we got. We live and we die, and I believe we come back again."

After years of breathing problems, emphysema and pneumonia, Willie stopped smoking weed at the age of 86, but he still enjoys edibles and gets a lot of pleasure particularly from his wife Annie D'Angelo's marijuana-infused chocolate because he can get high without pain.

He said: "I had a lung collapse, so I have to be really careful. I do edibles at night."

The Crazy hitmaker believes the drug has made him a better songwriter.

He explained: "It relaxes you to a point where you might think a little different."

Despite sustaining an active career, Willie's life has been so much simpler over the last few decades that he feels like he retired a long time ago.

He laughed: "I have been retired for 50 years!"

Willie previously credited marijuana for saving his life.

He told E! News: "[Marijuana] not only saved my life, it probably saved some other people's lives because before I smoked marijuana, I was drinking a lot. And I might have killed a lot of people, too. So I'm just glad that that didn't happen. I'm glad we live through all of bad times."